Omnidirectional treadmill system

ABSTRACT

The invention provides an omnidirectional treadmill system that uses an inner core which is inflated within a tread membrane. On the outside surface of the inflated inner core are ball casters which push outward against the interior of the membrane, resulting in a low friction barrier between the inner core and the inside surface of the tread membrane. The tread membrane rests on a sphere directly below the user in the center of the device. When the sphere is rotated it drives the tread around the stationary inner core. The sphere rotation is accomplished using a holonomic drive system such as motorized omni wheels. The device uses an enclosure which encircles the tread area. The enclosure serves two purposes: to enhance safety of the user and to provide a surface for image projection to the user in virtual reality applications.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patentapplication No. 63/300,083 filed on Jan. 17, 2022, the content of whichis incorporated herein by reference in its entirety.

TECHNICAL FIELD

Embodiments disclosed herein relate generally to an omnidirectionaltreadmill system, and more specifically to an omnidirectional locomotionapparatus that can be used in conjunction with virtual reality systems.

BACKGROUND ART

An omnidirectional treadmill (ODT) is a mechanical device that allows auser to perform locomotive motion while remaining in a fixed location.Unlike a traditional belt treadmill where the user is limited tomovement in a single direction, an omnidirectional treadmill allows theusers to perform locomotive motion in any direction while remaining in afixed location. Omnidirectional treadmills are employed in immersivevirtual environments to allow unencumbered movement within a virtualspace.

Principal to omnidirectional treadmill design is maintaining the usercentered on a treadmill surface while they perform locomotive actions.There have been various methods employed in the prior art, among them isa design where the treadmill surface consists of a spherical treadmembrane which is rotated around an inner core which remains in a fixedposition. The rotation of the tread membrane is coordinated with theusers' movement such that the user remains centered on the top surfaceof the tread. These prior art omnidirectional systems utilize a varietyof design approaches which result in limitations in their utility forvirtual reality applications.

Therefore, there is a need in virtual reality applications for anomnidirectional treadmill system that is safe, cost effective andsupports higher rates of unencumbered user locomotion.

SUMMARY OF THE EMBODIMENTS

The present invention provides an omnidirectional treadmill system thatuses an inner core which is inflated within a tread membrane. The treadmembrane is spherical in shape prior to being stretched by the innercore. The inner core is torus (donut) shaped and when inflated withinthe tread membrane, stretches the tread membrane to provide a flatsurface which the user moves upon. On the outside surface of theinflated inner core are ball casters which push outward against theinterior of the membrane, resulting in a low friction barrier betweenthe inner core and the inside surface of the tread membrane.

The tread membrane rests on a sphere directly below the user in thecenter of the device. The weight of the tread resting on the sphereprovides additional tension to the tread surface and enhances thetraction of the sphere. When the sphere is rotated it drives the treadaround the stationary inner core. The sphere rotation is powered using aholonomic drive system such as motorized omni wheels.

The device includes an outer frame to hold the rotating sphere in afixed position and to maintain the tread membrane centered on thesphere. The outer frame may include linear actuators which alter thehorizontal slope of the tread surface while keeping the sphere in afixed position. The outer frame has attached ball casters at pointswhere it contacts the tread membrane.

Attached to the outer frame, the device includes an enclosure whichencircles the tread area. The enclosure enhances the safety of thedevice and provides a surface for image projection to the user forvirtual reality applications.

The device includes one or more motion cameras configured to providethree-dimensional kinematic analysis of the user's movement while on thedevice. The user bone analysis is used by the device to:

-   -   a. maintain the user centered on the device using the rotating        sphere;    -   b. to map the user's actions to actions in a virtual        environment;    -   c. to control safety features if the user falls; and    -   d. to control other features on the device, such as the linear        actuators.

Other aspects, embodiments and features of the system and method willbecome apparent from the following detailed description when consideredin conjunction with the accompanying figures. The accompanying figuresare for schematic purposes and are not intended to be drawn to scale. Inthe figures, each identical or substantially similar component that isillustrated in various figures is represented by a single numeral ornotation. For purposes of clarity, not every component is labeled inevery figure. Nor is every component of each embodiment of the deviceand method shown where illustration is not necessary to allow those ofordinary skill in the art to understand the device and method.

BRIEF DESCRIPTION OF THE DRAWINGS

The preceding summary, as well as the following detailed description ofthe disclosed system and method, will be better understood when read inconjunction with the attached drawings. It should be understood,however, that neither the system nor the method is limited to theprecise arrangements and instrumentalities shown.

FIG. 1 is a schematic cross-sectional view of a disclosedomnidirectional treadmill system embodying the invention.

FIG. 2 is a schematic cross-sectional view of a disclosedomnidirectional treadmill system embodying the invention with a fullyenclosing inflatable with a projected virtual environment system andactuating gears to alter the tread slope.

FIG. 3 is a perspective view of the disclosed omnidirectional treadmillsystem.

FIG. 4 is a perspective view of the inflatable inner core with ballcaster barrier.

FIG. 5 is an illustration of the holonomic drive system incorporating aplurality of omni wheels coupled to the motors.

FIG. 6 is a perspective view of the inflatable inner core with a hardtread deck.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring now to the drawings in detail, FIG. 1 shows a cross-sectionalview of an omnidirectional treadmill system 100 that includes a treadmembrane 160 which has been stretched around an inflated inner core 120.The inflated inner core 120 has attached ball casters 140 which providea low friction barrier between the tread and the inner core. The treadand inner core rests on a sphere 110 which allows omnidirectionalmovement of the tread around the inner core 120. The sphere is driven bya holonomic drive system 130 which in this preferred embodiment usesmotorized omni wheels 134 coupled to a corresponding motor 132 and shaft133 (as shown in more detail in FIG. 5 ). In a preferred embodiment ofthe present invention, the holonomic drive system includes four omniwheels, which are wheels with small discs (rollers) around thecircumference which are perpendicular to the turning direction.

The outer frame 170 maintains the tread centered on the sphere. Theouter frame 170 has an attached barrier 150 which encircles the treadmembrane 160. Situated around the outer frame are motion cameras 190which provide kinematic analysis of the user. The outer frame 170 can bemade of a stiff material such as aluminum tube.

FIG. 2 is a cross-sectional view with similar features to FIG. 1 withthe following additional features. The FIG. 2 omnidirectional treadmillsystem 100 includes linear actuating motors 180 attached to the outerframe 170 to alter the horizontal slope of the tread. A dome barrier 150fully encloses the tread membrane 160; and the system furtherincorporates a projected light virtual environment system 175 thatincludes one or more projectors 176 affixed around the perimeter of thedome to project light 176 on surfaces on the enclosed interior.

FIG. 3 is a perspective view of an omnidirectional treadmill with treadmembrane 160, inflated enclosure 150, outer frame 170, and user motioncameras 190.

FIG. 4 is a perspective view of the inflated inner core 120, the treadsphere 110, and the holonomic drive system 130. The inflated inner core120 includes a plurality of ball casters 140 disposed on a plurality ofcorresponding rings 142 encircling the inflated inner core 120 forproviding the contact points with the tread membrane. The system furtherincludes an inner frame 171 made from a stiff material such as aluminumpipe to provide for the structural integrity of the inflated inner core120 and to support a tread deck 172 under the tread surface.

The system of the present invention may include safety and trampolinefeatures which minimize injuries associated with falling while utilizingthe device. The system may include a hard tread deck 172 below the treadsurface to support the user's weight while on the device, as shown inFIG. 6 , for example. Below the tread deck 172 the device may provide ameans for the tread deck to quickly be vertically lowered and raisedusing an actuating device such as pneumatic actuators. The system canfurther include one or more motion cameras 190 configured to determinethe user's bone positions on the surface of the treadmill in threedimensional space. Using the motion camera(s), the device may determinethat the user is in the process of falling and lower the tread deckvertically at a high rate of speed. When the tread deck is verticallylowered, the falling user impacts the taut tread surface, but theirimpact no longer reaches the hard tread deck. The result is the user'sweight falls only upon the flexible tread, similar to a trampoline,resulting in a softened landing and minimizing injury risk. Similarly,the device may vary the vertical distance of the tread deck from thetread to support trampoline effects for user movement.

While at least one exemplary embodiment has been presented in theforegoing detailed description of the invention, it should beappreciated that a vast number of variations exists. It should also beappreciated that the exemplary embodiment or exemplary embodiments areonly examples, and are not intended to limit the scope, applicability,or configuration of the invention in any way. Rather, the foregoingdetailed description will provide those skilled in the art with aconvenient road map for implementing an exemplary embodiment of theinvention, it being understood that various changes may be made in thefunction and arrangement of elements described in an exemplaryembodiment without departing from the scope of the invention as setforth in the appended claims and their legal equivalents.

Although the invention is described herein with reference to specificembodiments, various modifications and changes can be made withoutdeparting from the scope of the present invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope of thepresent invention. Any benefits, advantages, or solutions to problemsthat are described herein with regard to specific embodiments are notintended to be construed as a critical, required, or essential featureor element of any or all the claims.

Unless stated otherwise, terms such as “first” and “second” are used toarbitrarily distinguish between the elements such terms describe. Thus,these terms are not necessarily intended to indicate temporal or otherprioritization of such elements.

The foregoing detailed description is merely exemplary in nature and isnot intended to limit the invention or application and uses of theinvention. Furthermore, there is no intention to be bound by anyexpressed or implied theory presented in the preceding technical field,background, brief summary, or the following detailed description.

What is claimed is:
 1. An omnidirectional treadmill system, comprising: a tread membrane stretched around an inflated inner core; a plurality of ball casters attached to the inflated inner core for providing a low friction barrier between the tread membrane and the inner core; wherein the thread membrane and the inner core rest on a sphere which allows omnidirectional movement of the tread membrane around the inner core; and wherein the sphere is driven by a holonomic drive system.
 2. The system of claim 1, wherein the holonomic drive system comprising a plurality of motorized omni wheels each coupled to a corresponding motor and shaft.
 3. The system of claim 1, further comprising an outer frame for maintaining the tread membrane centered on the sphere.
 4. The system of claim 3, wherein the outer frame further comprising an attached barrier encircling the tread membrane.
 5. The system of claim 3, further comprising one or more motion cameras for providing kinematic analysis of the user to control the holonomic drive system.
 6. The system of claim 3, further comprising a plurality of linear actuating motors attached to the outer frame for altering the horizontal slope of the tread.
 7. The system of claim 1, further comprising a dome barrier fully enclosing the tread membrane.
 8. The system of claim 1, further comprising a projected virtual environment system having one or more projectors on the perimeter of the dome barrier; wherein projected light emitted by the system is used to provide a virtual environment to a user.
 9. The system of claim 1, wherein the plurality of ball casters are disposed on a plurality of corresponding rings encircling the inflated inner core for providing the contact points with the tread membrane.
 10. The system of claim 1, further comprising an inner frame for providing structural integrity of the inflated inner core.
 11. The system of claim 1, further comprising a tread deck attached to the inner frame below the tread which contains a mechanism for vertically actuating the deck.
 12. The system of claim 1, further comprising one or more motion cameras used by the device to determine a user's bone positions on the surface of the tread to control the mechanical aspects of the device and to map user actions to actions in virtual reality. 